<html>
    <head >
        <script src="18.js">
        </script>
    </head>
    <body onload="load()">
        <div id="operation">
            <input type="text" id="input">
            <button id="left_in">left_in</button>
            <button id="right_in">right_in</button>
            <button id="left_out">left_out</button>
            <button id="right_out">right_out</button>
        </div>
        <div id="selectNum">
           
        </div>
    </body>
</html>